Ok here goes, have a 2003 90cc and my son was riding and it quit. When I went to restart it would do nothing. Pulled off all the plastic and here is what I have found:

- Tail light is not working
- no responce form starter, but have jumped it and the starter works, but no spark
- Checked the break switch and it does make contact when checking it with a meter
- Tried a different CDI box and it does the same thing
- Almost seems like I've lost a ground, I took a short piece of wire and stuck it in between the connection from the brake switch, and just held it to the frame and then when I hit the starter it turns over. but still no spark. Oh and when I did jump this the tail light would come on with the brake lever pulled.

I've looked it over pretty well and cant't find a broken/loose wire any where. I'm kind of confused about the tail light. It has 3 wires coming in the plug and 2 going out to the light. How would it have a tail and stop light with only 2 wires?

Thanks in advance for any help!
Tim

 

The starter interlock switch on the left brake lever doesn't have anything to do with spark. It just controls the brake light and allows the starter to engage. Unplug the black wire from the cdi and see if you have spark. This eliminates the kill circuit.Plus you can jump the two safety switch wire together and see if you have spark. If still no spark,check the resistance on the stator wires leading to the cdi.BLACK to White/red wire should show 450 ohms resistance,Black to Blk/Red 800 ohms,Black to Yellow/Red 0.5 ohms,Black to White 0.6 ohms,Black to Ground should not zero out. Coil primary tab to ground 0.2 to 0.3 ohms. These specs are + or - 20%. Most of the problems I had were stator related with the little ones,but you can't rule out a cdi or coil.

 

Thanks for the responce OPT! Here is what I found so far. I did end up finding a broken Black/green stripe wire up near the head light. Snapped clear off. When I soldered that back together now the brake light works and the motor turns over like it is suppose to. But still no spark. So I was going to start testing the coil like you reccomended. I have had to replace the coil with a Rickey's aftermarket once before about 2-3 yrs ago. When I started l looking at that I noticed that the white wire in the 3 place plug was hanging out. (so much for the, no loose and broken wires statement I made before..) Upon closer inspection when the factory soldered the plug on the female part of the tab was wleded shut and would not recieve the male end. Didn't notice it when I put it on and it must have been making contact for some time and finnaly just wiggled out the back of the plug. I started testing the ohms with my meter but got kind of confused. My meter is kind of a cheap one and does not auto select the range. I'm wondering if by this wire loosing contac t if that ended up shorting out the stator?

 

Just check the resistance on the stator wires I gave you to eliminate the stator as the problem.If it checks out ok, then you can move on to see what else it may be..Plus along with stator and ground problems (for the most part) I've had ignition switch wiring that have come unsoldered. Pull the plastic cover at the back of it and see if any wire may be loose or touching another.

 

OK will do!
Thanks